PHOSPHOLIPASE-A ACTIVITY IN PSEUDOMONAS-AERUGINOSA

Our study describes the production, purification and properties of an enzyme from Pseudomonas aeruginosa displaying the properties of phosph olipase A. Maximal amounts of enzyme could be detected in the culture supernatant when the bacterium was grown for 3 to 5 days at 37 degrees C in stirred flask cultures containing brain heart infusion. The enzy me was purified by polyethylenimine precipitation and ammonium sulfate precipitation followed by gel filtration. In sodium dodecyl sulfate-p olyacrylamide gel electrophoresis, the enzyme preparation exhibited tw o bands with molecular weights of 13.5 and 60 kD, respectively. Corres pondingly, two peaks of the same molecular weight could be demonstrate d by high performance size exclusion chromatography. The activity towa rd the sn-2 ester binding of phospholipids was characterized and found to be highest towards phosphatidylcholine. Enzymatic activity was not influenced by the addition of calcium or EDTA while magnesium and str ontium caused a decrease of activity. The lyophilized enzyme was found to be stable when stored at -70 degrees C and most active at pH 8.0.